Control mechanism



July 1, 1969 R J NE1 SON ETAL CONTROL MECHANI SM Filed Aug. 24, 1967 INVENTORS ROGER J. NELSON 8 RICHARD TREICHEL FIG 4 United States Patent O US. Cl. 74-526 7 Claims ABSTRACT OF THE DISCLOSURE A device for locating the position of a control lever between the extremes of its travel, consisting of a guide bar and a stop locatable at any point thereon and the control lever being movable along the guide bar and limited in one direction by contact with the bottom edge of the stop.

BACKGROUND OF THE INVENTION This invention relates to the locating of a control lever in various positions between the extremes of its travel and finds particular utility in hydraulic control systems of the position-responsive type such as the one disclosed in the US. Patent to Worstell 2,477,710.

The idea of a device to locate a control lever in various desired positions with a provision for overtravel beyond the stop position is old, one such device being described in the US. Patent to Gleeson et a1. 2,900,836. Such devices allow an operator to remember the particular position of the control lever desired so that the exact position can be returned to at any time, travel of the control lever on either side of the stop position being possible but a conscious effort on the part of the operator being required to move the control lever past the stop. The device which is the subject of this invention has the advantage over devices previously known in that it is of much simpler construction and is thus more easily produced at less cost. It also has the advantage of being more quickly and easily adjusted than devices heretofore known.

The idea of a clamp with legs biased apart frictionally engaging a rod passing through openings therein is also known. In the present invention, however, the control lever imparts a twisting force to the near leg of the clamp as the lever contacts the bottom edge of the stop tending to decrease the angle between the leg and the bar and thus to increase the normal and hence the frictional force between the stop and the rod. This is advantageous in that the larger the force of the control lever against the stop the more effectively the stop will maintain its position on the guide bar.

SUMMARY OF THE INVENTION The invention resides in a one-piece stop which slide-s easily from one fixed position to another on a guide bar against which a control lever slides, the stop acting to locate the control lever in any desired position along the guide bar, said stop maintaining its position all the more firmly as the control lever strikes it, it being nevertheless possible for the control lever to move beyond the stop position. This device is simple in construction and inexpensive, allows easy selection of stop positions while atfording a positive location once the desired position is selected, is easily overridden by the control lever while still retaining its position as a future reference, will wear well and require little if any maintenance, and can easily be adapted for use in conjunction with a variety of different control levers. In addition a number of these devices may be used in conjunction with a single control 3,452,616 Patented July 1, 1969 lever, thus allowing an operator to recall several different control-lever locations.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of the adjustable stop mounted on the guide bar in its engaged position and locating the control lever. Phantom lines show the stop in its movable or release position.

FIG. 2 is an enlarged side view of the adjustable stop alone.

FIG. 3 is a front view of the adjustable stop.

FIG. 4 is an enlarged section along line 44 in FIG. 1.

FIG. 5 is a section along line 55 in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT The numeral 10 indicates an arcuate guide member or bar with upper surface 19 and lower surface 20 which is rigidly mounted on a machine such as, for instance, a tractor. A control lever 11 is suitably mounted as on a rockshaft 12 and turns through an are somewhat shorterv than the length of the guide bar. An adjustable stop 13 shaped generally in the form of a V with radial members or legs 21 and 22 (see FIG. 2) rides the guide bar 10 as shown in FIG. 1, the guide bar passing through and approximately perpendicular to slots 16 in legs 21 and 22, the legs pointing upwardly, and projections 23 riding against the sides of the guide bar 10 so as to provide less resistance to the travel of the stop along said guide bar.

The adjustable stop 13 is made of spring steel or like material and includes a biasing means 26 (here a permanent set to legs 21 and 22) which causes the legs 21 and 22 to repel each other and, when in their free position, to frictionally engage surfaces 19 and 20 of the guide bar 10 with edges 17 and 18 respectively of leg 22 and similarly for leg 21, and thus resist any movement of the stop along the guide bar. The adjustable stop 13 is easily relocated, however, by forcing its two legs 21 and 22 together as shown with phantom lines in FIG. 1 and sliding it along the guide bar to the newly desired location where the legs are once again released to their free position.

The control lever 11 is biased towards the guide bar 10 such that it slides along the guide bar as it moves. As the control lever 11 slides along the guide bar it eventually contacts the bottom edge 15 of the adjustable stop 13 which acts as a stop against the control lever and thereby prevents further travel of the latter. If the control lever 11 is forced against the stop 13, the stop resists such force and maintains its position through its frictional contact with the guide bar. As the force of the control lever against the stop increases, the force acting on edge 15 of the adjustable stop tends to twist leg 22 of the stop in a clockwise direction and thereby increases the force of the frictional contact between the stop and the guide bar. Thus the more firmly the control lever is pressed against the stop the more tightly the stop clings to the guide bar and retains its location despite considerable pressure from the control lever.

The adjustable stop 13 is easily by-passed, however, by a slight yet conscious effort on the part of the operator of the control lever 11. The control lever is merely forced in a transverse direction away from the guide bar 10 to such an extent that the control lever clears the outside edge 24 of the adjustable stop and then on past the stop. Although by-passed, the adjustable stop retains its location on the guide bar 10 and thus provides an exact later reference to the operator.

As an optional feature the adjustable stop 13 may have the upper portions of its radial members or legs 21 and 22 cut in the shape of tabs. These tabs 25 (shown in FIG. 3) may be coated with a resilient material 14 and provide a convenient means by which the operator may force said legs together when relocating the stop along the guide bar.

We claim:

1. In a control mechanism including a guide member having a top, bottom and sides, a control member movable relative to and along one side of the guide member, and an adjustable stop on the guide member for interrupting the travel of the control member by contact therewith, the stop comprising: a pair of divergent legs having substantially spaced outer ends and relatively close inner ends; each of the legs being provided with an aperture through which the guide member passes ap proximately perpendicular to the legs; each of the apertures having a vertical dimension slightly greater than the vertical dimension of the guide member; means. joining the inner ends of the legs and extending outwardly a suflicient distance to be contacted by the control member prior to the outer end of one of the legs; the legs being biased apart to normal positions in which they frictionally engage the top and bottom of the guide member; and the legs being squeezable to a release position so as to increase the angle between each of them and the guide member and thus relieve the frictional engagement of the legs with the guide member.

2. A control mechanism as in claim 1 wherein the adjustable stop is of spring steel with its legs bent to a permanent set such as to bias them apart to the normal positions in which they frictionally engage the guide member.

3. A device as in claim 1 wherein means are provided for a lateral movement of the control member away from the guide member such that the adjustable stop may be by-passed when the control member is forced away from said guide member in a lateral direction for a sufiicient distance to clear and move past said stop 4. A mechanism as in claim 1 wherein the portions of the legs bordering the apertures have spaced lateral projections for contacting and riding against the sides of the guide member as the stop is moved along said guide member.

5. A mechanism as in claim 1 wherein the legs of the stop have tabs afiixed to their outer ends.

6. A mechanism as in claim 5 wherein the tabs are coated with a resilient material.

7. A mechanism as in claim 1 wherein the guide member is arcuate in shape.

References Cited UNITED STATES PATENTS 839,746 12/1906 Fox 19770 1,3 89,477 8/1921 Beeman 74558.5 1,505,220 8/1924 Shay 24243.12 1,560,252 11/1925 Eshelman et a1. 7453l 2,216,354 10/ 1940 Pletcher 7453l X 2,511,393 6/1950 Worthington 91384 2,682,920 7/1954 Mueller.

2,894,774 7/ 1959 Dudash 24257 X MILTON KAUFMAN, Primary Examiner. 

